ESMO 2019 — Expert commentary: no hurry for radiotherapy in postoperative localised prostate cancer

  • Daniela Ovadia — Agenzia Zoe
  • Oncology Conference reports
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Expert commentary by Xavier Maldonado, Clinical Chief in Radiation Oncology, Hospital Universitari Vall d’Hebron, Barcelona.

  • It seems that an old question—whether men with localised prostate cancer can be spared radiotherapy after surgery—has a preliminary answer thanks to two studies presented here at ESMO.
  • According to RADICALS-RT, a phase 3 postoperative study that randomised patients to receive radiotherapy or observation in prostate cancer, there is no difference in disease recurrence at 5 years between men who routinely had radiotherapy shortly after surgery (within 4-6 months) and men who had radiotherapy later, if cancer came back. We now have evidence that observation should be the standard approach.
  • These results were strengthened by a meta-analysis—ARTISTIC—also presented at ESMO, combining results of RADICALS with two similar trials: RAVES and GETUG-AFU 17. ARTISTIC provides greater evidence to support the routine use of observation and to assess whether adjuvant radiotherapy may have a role in some groups of men.
  • ARTISTIC demonstrated that around 40% of the patients in the surgery-alone arm would never require adjuvant irradiation in the next 10 years of follow-up, so there is a large number of overtreated patients that undergo adjuvant radiotherapy and could avoid it.
  • These results will avoid or at least shorten the duration of treatment and allow better use of resources, as modern radiotherapy is sophisticated and expensive. But a strict follow-up will be needed to identify patients requiring salvage radiotherapy.
  • From Dr Maldonado's point of view as a clinician, radiotherapy means also fewer side effects: according to those studies, self-reported urinary incontinence was worse at 1 year and was nearly doubled in patients receiving radiotherapy compared with those who had standard care. And even severe urethral stricture was much less common in the standard-care groups compared with radiotherapy.
  • We also have data on the PSA demonstrating that there is no difference in biochemical progression-free survival.
  • Based on these results, the difference in 5-year event-free survival is around 1%.
  • In any case, let’s be cautious: longer follow-up is needed (the median follow-up in RADICALS-RT was 5 years) for the main endpoint of the study, which is freedom from distant metastases at 10 years, and to comprehensively report on toxicities.
  • The focus should be on identifying which patients still require adjuvant radiotherapy to avoid a very early local relapse and potential subsequent metastases.
  • Dr Maldonado suggested that we need to develop genomic classifiers to help decide the best management strategy for each patient, whether it should include only surgery or surgery plus radiotherapy, and when.